1. Field of the Invention
Embodiments of the present invention relate to vehicle seats.
2. Description of the Related Art
Japanese Laid-Open Patent Application No. 2005-103002 discloses a seatback of a vehicle seat. The seatback includes a frame member having a metal body frame and a resin body frame. The metal body frame is substantially of a rectangular configuration as viewed from the front. The metal body frame constitutes a framework of the seatback and an opening at its center. The metal body frame is formed of a tubular steel pipe having, for example, a circular cross-section.
The resin body frame is arranged at the center opening of the metal body frame. The resin body frame includes a hollow flat plate and a plurality of ribs. The plurality of ribs is provided in the hollow flat plate. The ribs protrude from an inner surface to an outer surface of the hollow flat plate. The ribs are arranged side by side and in the vertical direction at appropriate intervals. Due to its hollowness, the resin body frame is reduced in weight while maintaining rigidity due to the plurality of ribs. Thereby, the frame member has been reduced in weight for the purpose of achieving a reduction in vehicle weight, etc.
International Publication WO 2008/019981 A1 discloses a frame having left and right elongated portions extending vertically. One of the elongated portions has a composite member composed from a composite material having fibers. There is also a rib for reinforcing the composite member. The composite member has a body plate facing a lateral side of the seat, a front flange provided at a front end of the body plate, and a rear flange provided at a rear end of the body plate. The rib is formed from thermoplastic material and has a lattice-like configuration. The rib is disposed between the front and rear flanges and is bonded on the body plate.
However, there has been a demand for a frame member which can be efficiently reduced in weight while exhibiting sufficient rigidity.